Gypsum wallboard is commonly manufactured and sold with a thin layer of textured coating materials, such as a coating material containing relatively uniformly dispersed particles of sand. One method of applying such textured coating materials was by a rubber-covered roll-coater roll.
One problem that has been encountered in applying textured coating materials with a rubber-covered roll-coater roll has been in the way the edge portions along each side edge has less textured material per square inch than the balance of the wallboard face. It is believed that the pressure of the rubber applicator roll against the face of the wallboard results in the rubber protruding to a greater diameter immediately adjacent the board edges, causing the rubber just inward of each board edge to be bent upward slightly away from the board surface. This raised portion of rubber either tends to leave less textured coating material or it tends to slightly wipe off some coating material as it is flexed different from the flexing of the rubber in the other areas of the roll-coating surface. Regardless of the reason, the resultant starved edge areas are clearly noticeable and undesirable.
A simple and economical means for overcoming this problem of starved edges will be understood to be highly desirable.